THE FIRST CRYSTAL-STRUCTURE ANALYSIS OF CYCLODODECA-2,8-DIYNE-1,10-DIOLS

Cyclododeca-2,8-diyne-1,10-diol, (6), C12H16O2, and 1,10-dimethylcyclo dodeca-2,8-diyne-1,10-diol, (11), C14H20O2, have been prepared and the ir structures determined. Both crystallize in centrosymmetric space gr oups and the molecules have approximate C-2 symmetry. For compound (6) , the lengths of the triple bonds are 1.184(3) (C2=C3) and 1.189(3) An gstrom (C8=C9). The bond angles at the triple bonds (C1-C2=C3 and C8=C 9-C-10) deviate by less than 6 degrees from 180 degrees. For compound (11), the lengths of the triple bonds are 1.190(3) (C2=C3) and 1.188(3 ) Angstrom (C8=C9), and the bond angles at the triple bonds are close to 175.5 degrees. In both compounds, the two 3-hexyne chains maintain a 'crossed' arrangement whereas the two alkylene chains are arranged i n a manner similar to that described for unsubstituted cyclododecane.